The process of giving care to a person with a dementing illness is universally viewed as highly stressful. Results from many studies suggest that the strain of caregiving is responsible for deterioration in caregivers' mental health and possibly their physical health also. However, there are great individual differences in the ability of care- givers to cope with the situation. In fact, there is no direct relationship between level of impairment in the care recipient and the caregiver's reported stress. Characteristics of the caregiver, such as coping skills and social support, seem to be more important in predicting caregiver burden as well as the health consequences of such perceived stress. A characteristic of the caregiver which has not yet been system- atically examined is personality. Personality has been shown to affect health both directly and indirectly through coping strategies. Therefore, the primary aim of this study is to determine whether personality is related to mental and physical health among caregivers.Caregving is not a monolithic process. Therefore, a secondary aim is compare caregivers of cognitively impaired patients with caregivers of physically impaired patients because it is important to explore similarities and differences between these groups. A broad, long-term objective is to expand our understanding of relationships between personality, stress, and health in later life. The design of the study is cross-sectional. Participants will be 150 spouse caregivers of patients with probable diagnosis of Alzheimer's disease and 150 spouse caregivers of patients with a diagnosis of Parkinson's disease with no co-existing dementia. Variables to be examined are: mental health, physical health, personality, stress appraisal, coping, social support, caregiving history, and demographics. These will be collected by trained research assistants in the caregivers' homes using instruments with established validity and reliability. In order to limit the length of time of the in-home interview, some of the research instruments will be left with the subjects and mailed back to the PI. The same battery of instruments will be administered to both caregiving groups. A series of models will be estimated using structural equation modeling techniques to determine which model provides the closest fit to the data. It would be useful to be able to predict which caregivers are at greatest risk for negative health consequences in order to intervene or target resources effectively.